//圆角边框
@mixin radius($radius:10px,$side:''){
	@if($side){
		border-#{$side}-radius: $radius;
		-webkit-border-#{$side}-radius: $radius;//For Safari 4.3.3-
	}@else{
		border-radius: $radius;
		-webkit-border-radius: $radius;//For Safari 4.3.3-
	}
}
//椭圆边框
@mixin elliptic($width,$height){
	border-radius: #{$width/2}/#{$height/2};
	-webkit-border-radius: #{$width/2}/#{$height/2};//For Safari 4.3.3-
}
//透明度
@mixin opacity($value:0.5){
	opacity: $value;
	filter:alpha(opacity=$value * 100);//For IE8-
}
//盒子阴影
@mixin box-shadow($shadows:0px 4px 5px #666){
	box-shadow: $shadows;
	-webkit-box-shadow: $shadows;//For Safari 4.3.3- And Android 2.2-
}
//文本阴影
@mixin text-shadow($shadows:0px 4px 5px #666){
	text-shadow: $shadows;
}
//实例
.css3{
	width: 300px;
	height: 50px;
	border: 5px solid #099;
	text-align: center;
	line-height: 50px;
	vertical-align: top;

	@include elliptic(300px,300px);
	@include radius(5px,'top-left');
	@include radius(5px,'bottom-right');
	@include opacity(0.8);
	@include box-shadow();
	@include text-shadow();
}

.elliptic{
	//如何获取未明确定义的值？
	$width: 200px;
	$height: 200px;
	$border-width: 20px;
	$margin: 50px;
	$padding: 10px;
	margin: $margin;
	width: $width;
	height: $height;
	padding: $padding;
	border: $border-width solid #369;
	@include elliptic($width+$border-width*2+$padding*2,$height+$border-width*2+$padding*2);
}
